Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Growing world urban populations threatened by massive earthquakes

02.05.2003


A new study by a University of Colorado at Boulder geological sciences professor suggests one earthquake causing up to 1 million fatalities on Earth each century could occur unless more earthquake-resistant construction materials are implemented.



Professor Roger Bilham’s conclusions are based on a study of the world’s urban population growth in the 21st century, including the number of rapidly expanding “supercities” and their locations close to major fault lines that have caused past temblors.

Bilham will present a paper on the subject at the 2003 Seismological Society Meeting to be held April 30 to May 2 in San Juan, Puerto Rico.


In the pre-1600s few city populations exceeded 1 million people, he said. By 1950, there were 43 “supercities” with populations from 2 million to more than 15 million. “Today, there are nearly 200 supercities on Earth, and the number could double before world populations stabilize.” Roughly 8 million people have died globally as a result of building collapses during earthquakes in the past 1,000 years, he said, although the record is sketchy prior to 1600. “But it is clear that a four-fold increase in the annual death toll from earthquakes between the 17th and 20th centuries is linked to increased urbanization.”

The emergence of “supercities” has increased tenfold since 1700, he said. Of these, more than 40 are located within 120 miles of a major plate boundary or a historically damaging earthquake, including Jakarta, Indonesia, Tehran, Iran, and Mexico City. Mexico City now has a population of roughly 16 million.

“Fifty percent of the world’s supercities now are located near potential future magnitude 7.5 earthquakes,” said Bilham, who is a fellow of the Cooperative Institute for Research in Environmental Sciences based at CU-Boulder.

“A 1997 statistical analysis predicted a future fatality rate of 8,000 deaths per year,” discounting extreme events with fatality counts exceeding 30,000,” said Bilham. “However, such predictions have no utility in extreme events in the 21st century, when urban populations are expected to reach 6 billion worldwide.”

From 1998 to 2002, earthquakes have caused roughly 10,500 fatalities per year. Bilham said a “fractal distribution of fatality count versus the number of fatal earthquakes permits a grim glimpse of possible future earthquake disasters based on past events.”

There is an apparent link between the earthquake fatality count for each earthquake and the number of “fatal earthquakes,” he said. “Fewer people are killed in small earthquakes that happen frequently. Large fatality-count earthquakes occur infrequently,” he said. By averaging these data over a century it is possible to derive a relationship to predict rare, extreme events.”

According to Bilham’s calculations, each year one earthquake event kills 100 people, every two years one event kills 1,000 people, every five years a single event kills 10,000 and for every century, an earthquake kills 300,000.

“But the 300,000 people is probably an underestimate because the size of these huge cites doubled in the last century and are expected to double again in the next century,” he said. “We have never had such a devastating megaquake before, because it simply wasn’t possible. But now we have many more target cities and they are bigger than ever before.”

One of the questions now being asked is whether a 100-year “megaquake” is now possible? Nearly 100,000 people were killed by earthquakes in India in 2000, and recent research by Bilham and his colleagues indicate that at least one and perhaps as many as seven 8.1 magnitude to 8.3 magnitude earthquakes are overdue in the Himalayas facing northern India.

“A great earthquake could occur in a dozen other countries if it occurs near a supercity,” Bilham said.

Bilham believes there is room for optimism, though he characterizes the present era as the age of construction when 3 billion new dwellings presently are being planned for a future doubling of the world population. “We are in a remarkably good position to make these new buildings safe to live in,” he said.

"Earthquakes don’t kill people, but buildings and builders of inferior buildings do.”

Roger Bilham | EurekAlert!
Further information:
http://www.colorado.edu/

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>